With Zuul v2, the publishing happens from publish-docs/api-ref.
Let's simplify our scripts and publish with Zuul v3 from publish-docs
directly.
Add new jobs publishlang and publishbuild for Zuul v3 publishing.
Use existing publishlang-api and publishbuild-api for Zuul v2
publishing.
Remove now obsolete comment from doc-tools-check-languages.conf.
Change-Id: I32b29a34c571882cb4d7c542c543ea726e76a0b5